/*******************************************************************************************
 * Copyright (c) 2006-2009 Alex Robson, Rob Simmons, Craig Israel, and Rachel Twyford
 *
 * Use of this software in any form requires that you have both 
 * read and agreed to the following terms:
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation 
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 * Software is furnished to do so, subject to the following conditions: 
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 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
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 * documentation and/or other materials provided with the distribution.
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using System;
using System.Linq.Expressions;
using Nvigorate.Common.Reflection;
using Nvigorate.Relational.Mapping.Interface;
using Nvigorate.Extensions;

namespace Nvigorate.Relational.Mapping.Fluent
{
    /// <summary>
    /// Fluent assignments have the following convention:
    /// Non-key columns that have the same name as the property which are persistable but not nullable
    /// </summary>
    public class FluentAssignment
    {
        #region Fields

        internal bool nullable { get; set; }
        internal bool persistable { get; set; }
        internal string source { get; set; }
        internal string sourceField { get; set; }
        internal string target { get; set; }
        internal string targetField { get; set; }
        internal bool primaryKey { get; set; }
        internal int argumentIndex { get; set; }
        internal Type constructedType { get; set; }
        internal bool foreignKey { get; set; }
        #endregion
        
        #region Public Methods

        /// <summary>
        /// Defines this assignment as being the key or part of a compound key
        /// </summary>
        /// <returns></returns>
        public FluentAssignment AsKey()
        {
            primaryKey = true;
            return this;
        }

        /// <summary>
        /// Identifies a column name that does not match the property name
        /// </summary>
        /// <param name="column">The column name</param>
        /// <returns></returns>
        public FluentAssignment ToColumn(string column)
        {
            sourceField = column;
            return this;
        }

        /// <summary>
        /// Allows nulls to be persisted to the repository
        /// </summary>
        /// <returns></returns>
        public FluentAssignment Nullable()
        {
            nullable = true;
            return this;
        }

        /// <summary>
        /// Prevents this field from being persisted to the repository
        /// </summary>
        /// <returns></returns>
        public FluentAssignment ReadOnly()
        {
            persistable = false;
            return this;
        }

        public FluentAssignment ConstructorArgument(int argumentIndex)
        {
            argumentIndex = argumentIndex;
            return this;
        }

        /// <summary>
        /// Builds an IAssignment for use in a SourceMap
        /// </summary>
        /// <returns>An IAssignment for use in a SourceMap</returns>
        public IAssignment GetAssignment()
        {
            return new MemberAssignment()
                       {
                           Nullable = nullable,
                           Persistable = persistable,
                           PrimaryKey = primaryKey,
                           ForeignKey = foreignKey,
                           Source = new AssignmentPoint(source, sourceField),
                           Target = new AssignmentPoint(target, targetField),
                           IsConstructorArgument = argumentIndex >= 0,
                           ConstructedType = constructedType,
                           ArgumentIndex = argumentIndex
                       };
        }

        #endregion

        private void GetConstructedTypeInformation()
        {
            var parts = targetField.Split('.'); 
            if(parts.Length > 1)
            {
                constructedType = Reflector.GetMemberType(constructedType, parts[0]);
            }
        }

        public FluentAssignment(string table, Type targetType, string property)
        {
            persistable = true;
            source = table;
            sourceField = property;
            target = targetType.GetCleanAssemblyQualifiedTypeName();
            constructedType = targetType;
            targetField = property;
            argumentIndex = -1;
            GetConstructedTypeInformation();
        }
    }
}